Learn More
In many neural systems, sensory information is distributed throughout a population of neurons. We study simple neural network models for extracting this information. The inputs to the networks are the stochastic responses of a population of sensory neurons tuned to directional stimuli. The performance of each network model in psychophysical tasks is(More)
  • H S Seung
  • 1996
The brain can hold the eyes still because it stores a memory of eye position. The brain's memory of horizontal eye position appears to be represented by persistent neural activity in a network known as the neural integrator, which is localized in the brainstem and cerebellum. Existing experimental data are reinterpreted as evidence for an "attractor(More)
The equilibrium phenomenon of matching behavior traditionally has been studied in stationary environments. Here we attempt to uncover the local mechanism of choice that gives rise to matching by studying behavior in a highly dynamic foraging environment. In our experiments, 2 rhesus monkeys (Macacca mulatta) foraged for juice rewards by making eye movements(More)
The probability of choosing an alternative in a long sequence of repeated choices is proportional to the total reward derived from that alternative, a phenomenon known as Herrnstein's matching law. This behavior is remarkably conserved across species and experimental conditions, but its underlying neural mechanisms still are unknown. Here, we propose a(More)
To quantify performance of the goldfish oculomotor neural integrator and determine its dependence on visual feedback, we measured the relationship between eye drift-velocity and position during spontaneous gaze fixations in the light and in the dark. In the light, drift-velocities were typically less than 1 deg/s, similar to those observed in humans. During(More)
Experiments in several cell types revealed that local accumulation of phosphatidylinositol 3,4,5-triphosphate mediates the ability of cells to migrate during gradient sensing. We took a systematic approach to characterize the functions of the six putative Class I phosphatidylinositol 3-kinases (PI3K1– 6) in Dictyostelium by creating a series of gene(More)
We have used a novel phase-referenced heterodyne dual-beam low-coherence interferometer to perform what we believe are the first noncontact measurements of surface motion in a nerve bundle during the action potential. Nerve displacements of approximately 5-nm amplitude and approximately 10-ms duration are measured without signal averaging. This(More)
We present a method for studying synaptic transmission in mass cultures of dissociated hippocampal neurons based on patch clamp recording combined with laser stimulation of neurons expressing channelrhodopsin-2 (ChR2). Our goal was to use the high spatial resolution of laser illumination to come as close as possible to the ideal of identifying(More)
Perceptron learning of randomly labeled patterns is analyzed using a Gibbs distribution on the set of realizable labelings of the patterns. The entropy o f this distribution is an extension of the Vapnik-Chervonenkis (VC) entropy, reducing to it exactly in the limit of innnite temperature. The close relationship between the VC and Gardner entropies can be(More)